Here in the UK, it is just anarchy on cycle paths.
In some countries, pedestrians behave similarly to drivers and typically pass each other as cars would on a road. The UK is not such a country and when you approach another pedestrian you just have to figure how to pass each time. Passing to the left (as you would in a car) is no more likely than to the ...
Since the question isn't tagged as USA-specific, I found myself wondering about the situation in the UK. The Highway Code only mentions these paths once in the pedestrian section:
Routes shared with cyclists. Some cycle tracks run alongside footpaths or pavements, using a segregating feature to separate cyclists from people on foot. ...
In a 2 lane bike path cyclists should ride in the right lane and pedestrians should walk in the left lane.
Most walkers and joggers wear headsets and can not hear you coming up behind them. So telling them you are going to pass on the left is useless.